Improvement in magneto-electric machines



J'. GRAY,

MAGNETo-ELECTRIG MACHINE. N.18Z,Z73.

ngz.

N. PETERS, PHOTo-UTHOGR-APNER, WASHINGTON, D C.

Patented Sept. 19, 1876.

UNITED iSTATES PATENT OFFICE.

JOSEPH GRAY, OF SHEFFIELD, ENGLAND.

IMPROVEMENI'I iN MAGNETO-ELECTRIC MACHINES.

Specification forming part of Letters Patent No. 182,273, datedSeptember 19, 1876; application filed vAugust 11, 1876.

To all whom it may concern:

Be it known that I, JOSEPH GRAY, of Shefeld, England, have inventedImprovements in Electric Machines, of which the following is thespecication:

The object'of my invention is an improvement in magneto electricmachines in which a revolving coil and movable keeper are used; and myinvention consists in devices connected with the keeper, whereby thepower of the instrument may be indicated and regulated.

In the drawing, Figure l is a sectional elevation of a magneto-electricmachine with my improvements, the lid being raised to a verticalposition. Fig. 2 is a sectional plan on the line l 2, Fig. l; and Fig.3, an external plan, drawn to a reduced scale.

'Ihepermanent horseshoe-magnet A, the revolving cores B, driven by thewheel C, and the commutator s are constructed and arranged within a boX,D, in the ordinary manner.

The keeper E, which is necessary to insure currents ot' any greatcompass, is pivoted to the side of the box opposite the lower prongofthe magnet A, and to the upper end is jointed a `threaded rod, c,which extends through the end ot' the box, and through a revolving nut,b, by turning which the rod may be drawn in or out, and the upper endofthe keeper moved to or from the upper prong of the magnet, increasingthe intensity ot' the current in proportion as the keeper is Withdrawn.

It is of importance that those operating with such instruments formedical purposes should be able to vascertain the strength of thecurrent, so as to insurea uniform or gradually increased or diminishedcurrent, as desired.

Heretofore it has been usual to set the keeper by the eye, regulatingits position from day to day, as nearly as possible, in accordance withthe strength of current desired, but without it being possible todetermine with any accuracy its precise relative position. Moreover, inselling instruments for house use by the purchasers, it Was not possi--ble to dene any particular adjustment.

I overcome these difficulties by combining with the keeper a graduatedregistering device, by which the keeper may be definitely adjusted.

Various modes of arranging the register may be employed; but I preferthat shown in the drawing, in which a glass-covered graduated plate, d,at the outside of the lid ofthe case, is provided with a pointer orindicator, c, operated from the keeper, the position ofthe latter beingthus indicated without opening the case. v

In order that the movement of the lid may not att'ect the position ofthepointer, the keeper is connected by a ball-and-socket joint, x, to arod,f, jointed to an arm, g, of a guided rack, F, sliding in the lid andoperating a toothed wheel, m, which gears with a pinion, n, on thepointer-shaft. The arm g projects to such a position that' the movementsof the lid will carry it in a curve at all points equidistant from thejoint a2, so that but little, if any, motion of the rod Will result fromthe movement of the lid.

It will be apparent that the graduated plate may be arranged within thebox or at the end, and that the pointer may be connected in a differentmanner to the keeper.

Without, therefore, limiting myself to the precise arrangementdescribed, I claim- 1. The combination, in a magneto-electric machine,ofthe magnet, revolving cores, keeper E, adjustable, as set forth,graduated plate d, and a pointer, c, connected to devices operated bythe movement of the keeper, as specied.

2. The combination of the adjustable keeper, the graduated plate andpointer, carried by thelid, and the tlexible connections, Whereby thelid may be moved Without affecting the adjustment of the pointer.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

JosEPE GRAY.

Witnesses:

W. W. WooDEEAD, W. W. HIBBEET.

